Sometimes my toilet does not flush all the way but will eventually drain. (I have changed out the inside of the toilet) At the same time I hear a glurging in the sink in that bathroom. I also hear the same sound when I take a shower in the same bathroom. This does not occur in either of my other 2 bathrooms. Does this sounnd like a venting or clogged problem or my septic tank?

Doesn't sound like septic, possible clogging and a vent issue. Gurgling is venting related but doesn't mean the vent is blocked, it could be after the clog and the only way to vent is through another fixture. I would start with augering the toilet first.

Hmmm...sounds like a couple issues to me:

1) it sounds like you have a WET VENTED bathroom where the sink drain and sink vent act as a wet vent for the toilet and the shower. In this case, you would snake the sink drain and see if that eliminated the "glurging".

2) the toilet sounds like it is partially clogged. Start by making sure that the water level in the toilet tank is about a 1/2" below the top of the overflow pipe in the center of the toilet tank as that costs $0.00 to check...if water level is low set water level to proper depth by adjusting the toilet fill valve.

If the water level is correct and the siphon jet hole in the bottom of the toilet bowl is clear then that leaves a clogged toilet. Here, purchase a $30.00 closet auger from a local home improvement store and snake the toilet itself (see images). If that fails to resolve the issue then you may have to lift the toilet (or find a cleanout below the toilet) and snake the toilet drain line.

Mark

My first move with a slow flushing toilet is 3 quick buckets of water. If the water rises after the first bucket, plunge vigorously, then pour the second bucket if it goes down. Try flushing with the lid off since you have changed the guts in the toilet, maybe you need to readjust the water level or the refill hose.

Likely you have a clog but you may get lucky and clear it with a plunger. You may well have to get the auger out, though.

I have a different take on this, I have one that most repair plumbers miss.. Look down at the bottom of the bowl. If there is a small hole, then that is a jet that starts the syphon action. If it's clogged the water will just swirl around and slowly go down leaving solids behind. Take your finger,(UGH! ) and run it around the inside of the opening. Over the years minerals build up and cut down on the syphon (flush) action. If it is rough or you feel build up, take a table knife and put a bend in it to get around the curve in the bowl and chip and scrap it clear. Next take a coathanger and clear out the holes around the rim. They start the swirling action. And last, check the water level in the tank. It should be 1/2" below the top of the over flow tube. And speaking of the overflow tube, Make sure the small 1/8" tube from the ballcock to the white overflow tube is connected so it discharges in it and that it's flowing when the ballcock fills. This is what raises the water level in the bowl. For a good solid flush they all have to work together. Hope this helps. Good luck, Tom